This invention relates to absorbent products such as cosmetic wipes, sanitary napkins, diapers and catamenial tampons, comprising a pad of absorbent particulate matter. In the case of tampons, the pad is compressed into a desired, and generally cylindrical shape.
The aforementioned absorbent products in common use today are made up of absorbent particulate matter; most commonly of cellulosic fibers such as cotton, regenerated cellulose, i.e., rayon, and more recently of certain cellulosics which have been chemically modified to enhance their absorptivity, e.g., wet crosslinked cellulosics or grafted cellulose copolymers. Usually these fibers are formed into a loose, generally rectangular pad, and in the case of tampons, a withdrawal string is disposed around the pad and then the pad is wound or folded into the form of a blank which is then compressed in a die into the final tampon shape. In some cases, the blank or the compressed tampon is forced into a tampon applicator which is provided with a plunger and serves as a device for both retaining the tampon in the compressed form and for emplacing the tampon within the vagina of the user.
While, in the main, such tampons have been widely accepted and have functioned well, the art has been plagued by the problem known as sloughing. Sloughing, as related to tampons, is the release of particulate matter, and particularly fibers, from the surface of the tampon and the deposition of this released matter into the vagina. This release and deposition occurs primarily when inserting the dry tampon at which time frictional forces between the tampon and the walls of the vagina are greatest and tend to cause fibrous particulate matter to break loose.
Several methods have been suggested for alleviating the sloughing problem. Most commonly, the compressed tampon is provided with an outer cover of sheet material which is permeable to body fluids but which has sufficient wet strength to maintain its sheetlike integrity and act as an interface between the body of the tampon and the walls of the vagina. While this method is generally satisfactory, the incorporation of such a cover, usually comprised of such sheet material as nonwoven fabric, gauze and the like, has greatly impeded the high speed production of these tampons and, additionally, has added significantly to the cost of these tampons to the ultimate user. Further, under the stress imposed during use, not infrequently the cover material fails and not only does the cover then cease to be a shield against sloughing but instead actually adds to the problem by depositing pieces thereof in the vagina.
In view of the above problem, it has also been suggested, in U.S. Pat. No. 2,330,257, that the longitudinal sides of the tampon be provided with an occlusive, nonpermeable cover which has sufficient strength to insure that it will not come apart in use. While such a cover will in fact cure the problem with respect to cover failure, there is the concommitant drawback that those portions of the surface of the tampon so covered cannot transfer menses into the body of the tampon. Thus, any fluid which is not absorbed by the leading end of the tampon will remain unabsorbed.
In view of these drawbacks, it is apparent that no completely satisfactory solution has been heretofore provided for the sloughing problem.